A US aid worker, Warren Weinstein, has been held hostage by al Qaeda, the terror group's chief Ayman al-Zawahiri stated today in a video. He was kidnapped from Pakistan's Lahore city by armed men.

A US aid worker has been held hostage by al Qaeda, the terror group's chief Ayman al-Zawahiri stated on Thursday in a video.

Warren Weinstein was kidnapped from Pakistan's Lahore city by armed men, a news agency reported.

Al Qaeda abducted the elderly USAID contractor August 13. Zawahiri, in the video, termed him being "neck-deep in American aid to Pakistan".

Weinstein, a development expert, has lived in Pakistan for seven years and headed the office of an American contractor working for the US government's agency for international development to enhance Pakistan's dairy and gem trades.

"Just as the Americans detain whomever they suspect may be connected to al Qaeda or the Taliban even in the slightest of ways, we have detained this man who has been involved with US aid to Pakistan since the 1970s," said Zawahiri.

Zawahiri also said that the White House could secure his release by halting air strikes in Afghanistan, Pakistan, Somalia and Yemen, and releases the 1993 World Trade Centre bombers and relatives of Osama bin Laden.

Zawahiri, who had been a long-standing deputy to bin Laden, took over the al Qaeda chief's post this year after the latter was killed in a Pakistani town by US special forces in May.